1. Field of the Invention
The present invention relates to valve timing regulation device for varying the opening and closing timing of one or both of an air-intake valve and an exhaust valve in response to performance conditions of an internal combustion engine.
2. Description of Related Art
FIG. 22 is a partial cross-sectional view of a conventional valve timing regulation device disclosed for example in JP-A-10-331613. FIG. 23 is an enlarged cross-sectional view of a containing means.
In the figures, 101 is a cylindrical housing which is rotated by the output of the internal combustion engine. The housing 101 has a plurality of shoes 102 on an inner peripheral face. The shoes 102 extend in a radial direction of the housing 101. 103 is a timing sprocket connected to one axial end of the housing 101. The timing sprocket 103 is interlocked with the crankshaft of the internal combustion engine. 104 is a rotor which is housed to rotate relative to the housing 101. The rotor 104 is connected to a camshaft (not shown) which opens and closes the air-intake and exhaust gas valves of the internal combustion. A plurality of vanes 105 which project between mutual vanes 102 project from an outer peripheral face of the rotor 104. 106 is a retarding oil chamber for displacing each vane 105 in a retarding direction. 107 is an advancing oil chamber for displacing each vane 105 in an advancing direction. The retarding oil chamber 106 and the advancing oil chamber 107 are formed between the housing 101 and the rotor 104 by a space having a fan-shaped cross section which is formed between each vane 105 and each shoe 102. A working oil is supplied to the retarding oil chamber 106 and the advancing oil chamber 107.
108 is a seal mounting groove mounted on a tip of the vane 105. 109 is a containing means fitted and retained in the seal mounting groove 108. The containing means 109 comprises a seal member 110 having a spring housing groove 110a and a plate spring 111 housed in the spring housing groove 110a. The plate spring 111 presses the seal member 110 on the inner peripheral face of the housing 101.
The groove opening side from the groove base of the spring housing groove 110a of the seal member 110 has approximately a trapezoid cross sectional shape, the width of which gradually narrows. Thus both inner wall faces of the spring housing groove 110a are inclined wall faces 110b. On the other hand, the plate spring 111 has a leg piece 111b with an expanding shape provided on both edges of the central curved section 111a. The central curved section 111a has a cross sectional shape approximately in the shape of a circular arc. Before mounting the plate spring 111 with respect to the spring housing groove 110a, the plate spring 111 is formed so that the open leg width of the leg piece 111b is wider than the width of the opening of the spring housing groove 110a. 
When assembling the containing means 109, the leg piece 111b is pressed into the spring housing groove 110a of the seal member 110 while compressing the open leg width of the leg piece 111b of the plate spring 111. The pressing of the leg piece 111b allows the leg piece 111b to be pressed onto and engaged with both inclined wall faces 110b of the spring housing groove 110a. Furthermore the tip of the leg piece 111b abuts with the bottom face of the spring housing groove 110a. In this position, the seal member 110 and the plate spring 111 are assembled integrally. A containing means 109 assembled in such a manner is inserted and fitted into the seal mounting groove 108 of the vane 105 during assembly of the housing 101 and the rotor 104. When inserted and fitted, the seal member 110 is pressed onto the inner peripheral face of the housing 101 by the repulsive force of the plate spring 111. Thus the sliding face of the vane 105 and the inner peripheral face of the housing 101 are sealed by the seal member 110.
Since a conventional valve timing regulation device is comprised in the above manner, the leg piece 111b must be pressed into the spring housing groove 110a of the seal member 110 while compressing the leg piece 111b of the plate spring 111 during assembly of the containing means 109. As a result, the problem has arisen that the mounting operation of the plate spring 111 with respect to the seal member 110 is difficult and requires considerable time. Furthermore the mounting of the containing means 109 on the valve timing regulation device is performed by inserting the containing means 109 from one end into the seal mounting groove 108 of the tip of the vane 105 with the rotor 104 fitted into the housing 101. Thus during insertion, it is necessary to deform the plate spring 111 resiliently towards the bottom face of the spring housing groove 110a. However the plate spring 111 is fixed with the leg piece 111b of the plate spring 111 abutting under pressure with both inclined wall faces 110b of the spring housing groove 110a and the tip of-the leg piece 111b abutting with the bottom face of the spring housing groove 110a. As a result, it is difficult to create resilient deformation when insertion into the seal-mounting groove 108 is performed. Thus the problem has arisen that it is difficult to mount the containing means 109 with respect to the valve timing regulation device.
It has been proposed to reduce the spring constant of the plate spring more than necessary in order to solve the above problem. Thus in order to reduce the spring constant, it is necessary to reduce the width of the plate unnecessarily or to reduce the thickness of the plate. However such methods entail the disadvantage that durability of the components can not be maintained and breakage or damage of the plate spring occurs.
Other techniques about the conventional valve timing regulation device are disclosed for example in JP-A-11-30111. Since this valve timing regulation device has the object of preventing positional deviation of the plate spring in a transverse direction, the device does not comprise a detachment prevention structure for the plate spring and the seal member. As a result, when the seal member is assembled into the seal mounting groove, it is necessary to mount the seal member by insertion into the seal mounting groove while retaining the plate spring stored in the seal member mechanically or manually.
This type of mounting operation easily leads to detachment or separation of the plate spring during mounting. Thus for example, when mounting manually, unnecessary mounting time is required. Furthermore when mounting manually, designated mounting tools are required. Also a special detection means is required to detect detachment of the plate spring. In such a manner, unnecessary time is required for the mounting process or preparation for the mounting process. Thus productivity suffers greatly and as a result, the problem of increased costs results.
The present invention is proposed to solve the above problem and has the object of providing a valve timing regulation device which provides the seal member and plate spring as a pre-assembled unit and which allows easy insertion of both above components between the sliding peripheral faces of a first rotating body and a second rotating body. This arrangement results in improvements in productivity.
The present invention has the further object of providing a valve timing regulation device which allows the further simplification of insertion of the seal member, provided as a pre-assembled unit with the plate spring, between the sliding peripheral faces of the first rotating body and the second rotating body.
The present invention has the further object of providing a valve timing regulation device which allows smooth insertion of the seal member between the sliding peripheral faces of the first rotating body and the second rotating body. After mounting of the seal member and plate spring, this ensures prevention of separation of both above components.
The present invention has the further object of providing a valve timing regulation device which further ensures prevention of separation of the seal member and plate spring after assembly of both these components.
The present invention has the further object of providing a valve timing regulation device which allows smooth fitting of the plate spring into the inner section of the seal member without any resistance and which ensures prevention of separation of the unit comprising the plate spring and seal member after the fitting operation.
The present invention has the further object of providing a valve timing regulation device which allows improvements in mounting productivity of the plate spring with respect to the seal member and allows simple fitting into the inner section of the seal member without interference of the plate spring with the seal member.
The present invention has the further object of providing a valve timing regulation device which prevents deformation of the seal member resulting from deficiencies in strength.
The present invention has the further object of providing a valve timing regulation device which allows simple mounting of the plate spring with respect to the seal member.
The present invention has the further object of providing a valve timing regulation device which allows for self-lubrication of the seal member and thus reduces wear of the seal member. Furthermore by reducing frictional resistance, it is possible to facilitate relative rotation of the first rotating body and the second rotating body.
The present invention has the further object of providing a valve timing regulation device which allows mounting of the plate spring into the inner section of the seal member without interference to the seal member by only applying a bending deformation to the plate spring. After mounting, this ensures that the plate spring does not detach from the inner section of the seal member.
The present invention has the further object of providing a valve timing regulation device which further simplifies mounting of the plate spring with respect to the seal member.
The present invention has the further object of providing a valve timing regulation device which allows simple press-fitting of the spring pressing member into the inner section of the seal member as a guide for the plate spring which is fitted into the inner section of the seal member.
The present invention has the further object of providing a valve timing regulation device which allows simple press-fitting and guiding of the spring pressing member into the inner section of the seal member as a guide for the plate spring which is fitted into the inner section of the seal member. Furthermore it is possible to ensure the integration of the plate spring with respect to the seal member by the spring pressing member without instability.
Furthermore the present invention has the further object of providing a valve timing regulation device which retains a plate spring in a stable manner on an inner section of the seal member, and strongly engages the plate spring resiliently with respect to the seal member. Thus integration of both components can be ensured.
According to a first aspect of the present invention, there is provided a valve timing regulation device comprising: a first rotating body having a plurality of shoes on an inner peripheral face, the first rotation body being rotated by an output of an internal combustion engine; a second rotating body having a plurality of vanes on an outer peripheral face of a boss, the second rotating body stored to rotate relative to an inner section of the first rotating body and connected directly to a cam shaft of a system opening and closing at least one of an air-intake or exhaust valve of the internal combustion engine; a retarding oil pressure chamber and an advancing oil pressure chamber formed between the first rotating body and the second rotating body, and between the shoes and vanes; a seal mounting groove provided on the tip of the shoes and the vanes; a seal member which is indented in cross section and is inserted into the seal mounting groove; a plate spring biasing the seal member in a direction of abutment with an inner peripheral face of the first rotating body or with an outer peripheral face of the boss of the second rotating body, both ends of the plate spring fitted to an inner section of the indentation of the seal member; and a spring fixing means provided on the seal member which suppresses detachment of the plate spring and allows displacement due to elastic deformation of the plate spring.
Here, the seal member may have a tapering face inclined to isolate an end face of the seal member, the tapering face being arranged on at least one end in a longitudinal direction and near the open end of the indented inner section.
The plate spring may comprise a central curved section, and an outwardly bent piece formed on both ends of the central curved section, the outwardly bent piece being fixed with a play between the inner bottom face of the seal member and the spring fixing means.
The plate spring may comprise a central curved section, and an inwardly bent piece formed on both ends of the central curved section, the inwardly bent piece holding the spring fixing means.
The spring fixing means may comprise a cover fitted and engaged with both longitudinal ends on the open end of the indented inner section of the seal member, and covering both ends of the plate spring fitted into the inner section of the seal member.
The valve timing regulation device may further comprise: a fixing projection provided as a spring fixing means on both inner side faces of the seal member; and a notched section having a shape allowing passage of the fixing projection and not interfering with the fixing projection, the notched section being provided on an end face in a transverse direction of the plate spring which biases the seal member, the notched section being retained at a position not aligned with the fixing projection which is a position storing the plate spring with respect to the inner section of the seal member.
The seal member may form a reinforcing cladded section on an inner bottom corner on both longitudinal sides of the seal member.
The spring fixing means may comprise a fixing projection which projects from both inner lateral faces of the seal member and which is opposite to a position sandwiching both edges of the plate spring to create a space with the inner bottom face of the seal member.
The seal member may be formed from a resinous material having self-lubrication properties.
The plate spring may comprise a central curved section, and an outwardly bent piece formed on both ends of the central curved section, the outwardly bent piece being fixed with a play between the inner bottom face of the seal member and the fixing projection, a notched section being formed on an end face in a transverse direction of the outwardly bent piece.
The notched section may be formed on the outwardly bent piece on one end of the plate spring.
The fixing projection may be formed with a hemispherical, circular cross-sectional or elliptical cross-sectional shape.
According to a second aspect of the present invention, there is provided a valve timing regulation device comprising: a first rotating body having a plurality of shoes on an inner peripheral face, the first rotation body being rotated by an output of an internal combustion engine; a second rotating body having a plurality of vanes on an outer peripheral face of a boss, the second rotating body stored to rotate relative to an inner section of the first rotating body and connected directly to a cam shaft of a system opening and closing at least one of an air-intake or exhaust valve of the internal combustion engine; a retard oil pressure chamber and an advancing oil pressure chamber formed between the first rotating body and the second rotating body, and between the shoes and vanes; a seal mounting groove provided on the tip of the shoes and the vanes; a seal member which is indented in cross section and is inserted into the seal mounting groove; opposed engaging projections provided with respect to both inner faces of the seal member; a plate spring fitted into the indented inner section of the seal member, and biasing the seal member in a direction of abutment with an inner peripheral face of the first rotating body or an outer peripheral face of the boss of the second rotating body, a spring pressing member having a hole for fitting onto the central curved section formed on the plate spring, the spring pressing member press-fitted between the inner face of the seal member and the edge of the plate spring and engaging with the fixing projection to cover both ends of the seal member, and the plate spring having a smaller width than the corresponding interval of the fixing projection.
Here, the spring pressing member may be formed as a flat rectangular frame having a hole for fitting the central curved section of the plate spring with a play, a side plate section on both longitudinal sides of the spring pressing member being in contact with both edges of the seal member and being press-fit to the inner section of the inner section of the seal member through the fixing projection.
According to a third aspect of the present invention, there is provided a valve timing regulation device comprising: a first rotating body having a plurality of shoes on an inner peripheral face, the first rotation body being rotated by an output of an internal combustion engine; a second rotating body having a plurality of vanes on an outer peripheral face of a boss, the second rotating body stored to rotate relative to the inner section of the first rotating body and connected directly to a cam shaft of the system opening and closing at least one of an air-intake or exhaust valve of the internal combustion engine; a retarding oil pressure chamber and an advancing oil pressure chamber formed between the first rotating body and the second rotating body, and between the shoes and vanes; a seal mounting groove provided on the tip of the shoes and the vanes; a seal member which is indented in cross section and is inserted into the seal mounting groove; a fixing step for fixing the spring, the fixing step provided on both end faces of the seal member; a plate spring formed in a waveform having a backwardly curved section on both ends of the central curved section, the end of the backwardly curved section resiliently engaging with the fixing step, the stem of each backwardly curved section abutting at two positions on the inner bottom face of the seal member, the plate spring biasing the seal member in a direction of abutment with respect to an outer peripheral face of the boss of the second rotating section or an inner peripheral face of the first rotating section, and spring deformation preventing projections projecting from the inner bottom central section of the seal member and creating a space with the central curved section of the plate spring.